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tcp: Add mark for TIMEWAIT sockets

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This version has some suggestions by Eric Dumazet:

- Use a local variable for the mark in IPv6 instead of ctl_sk to avoid SMP
races.
- Use the more elegant "IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark"
statement.
- Factorize code as sk_fullsock() check is not necessary.

Aidan McGurn from Openwave Mobility systems reported the following bug:

"Marked routing is broken on customer deployment. Its effects are large
increase in Uplink retransmissions caused by the client never receiving
the final ACK to their FINACK - this ACK misses the mark and routes out
of the incorrect route."

Currently marks are added to sk_buffs for replies when the "fwmark_reflect"
sysctl is enabled. But not for TW sockets that had sk->sk_mark set via
setsockopt(SO_MARK..).

Fix this in IPv4/v6 by adding tw->tw_mark for TIME_WAIT sockets. Copy the the
original sk->sk_mark in __inet_twsk_hashdance() to the new tw->tw_mark location.
Then progate this so that the skb gets sent with the correct mark. Do the same
for resets. Give the "fwmark_reflect" sysctl precedence over sk->sk_mark so that
netfilter rules are still honored.

Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jon Maxwell
2018-05-10 16:53:51 +10:00
committed by David S. Miller
parent 03bdfc001c
commit 0048369055
5 changed files with 22 additions and 4 deletions
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6
net/ipv6/tcp_ipv6.c
View File

@@ -803,6 +803,7 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
unsigned int tot_len = sizeof(struct tcphdr);
struct dst_entry *dst;
__be32 *topt;
__u32 mark = 0;
if (tsecr)
tot_len += TCPOLEN_TSTAMP_ALIGNED;
@@ -871,7 +872,10 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
fl6.flowi6_oif = oif;
}
fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark);
if (sk)
mark = (sk->sk_state == TCP_TIME_WAIT) ?
inet_twsk(sk)->tw_mark : sk->sk_mark;
fl6.flowi6_mark = IP6_REPLY_MARK(net, skb->mark) ?: mark;
fl6.fl6_dport = t1->dest;
fl6.fl6_sport = t1->source;
fl6.flowi6_uid = sock_net_uid(net, sk && sk_fullsock(sk) ? sk : NULL);